1. Field of the Invention
The present invention relates to a laser distance-measuring apparatus and control methods thereof.
2. Description of the Related Art
Conventional laser distance-measuring apparatuses comprise an optical system to measure distance. However, most conventional optical distance measuring systems have a limited short-range cut off point. Specifically, most conventional optical distance measuring systems are limited to measuring distance ranges of over 0.3 meters. Thus, if the target to be measured is located under 0.3 meters, the reflected emitted light incident angle from the target will be too large, so that the receiver will not be able to appropriately receive the reflected emitted light and thus the target distance can not be calculated.
U.S. Pat. No. 5,949,531 discloses a distance-measuring apparatus in which a receiver is attached on one end of a leafspring, while the opposite end is fixed onto the body of the distance-measuring apparatus. A cam under the leafspring is rotated, so that the position of the receiver is changed according to the rotating cam. While the invention makes it capable for a laser distance-measuring apparatus to measure short-ranged distances, due to the leafspring and the cam, the distance-measuring apparatus requires a large volume, which is inconvenient for users. Additionally, during usage, due to the position of the leafspring and the cam, the rotating mechanism may easily wear out or be defective, wherein the receiver is positioned with a deviation.